This invention relates to instrument transformers and more particularly to dry-type instrument transformers with potential taps and to connector modules mating with such potential taps.
In the metering and control art it is well known to use instrument transformers such as potential transformers and current transformers to isolate high voltage circuits and provide a means of transforming voltage or currents to values that are convenient to measure or use in control circuits. In the metering art, it is often desirable to interconnect current transformers and potential transformers to obtain desired values for metering. In such interconnecting, it is necessary to provide a potential connection between the high voltage terminal of the current transformer and the high voltage terminal of the potential transformer. With present day dry-type instrument transformers the connection between such high voltage terminals is often made by means of clamp type connections which must be tapped or otherwise shielded to eliminate dangerous potentials. With the advent of dead-front connections and pad mounted equipment, it is considered desirable to provide dry-type instrument transformers with potential taps whereby such transformers may be interconnected for metering applications while still maintaining the dead-front connections. Also, for mounting in enclosed spaces, it is desirable to provide ground shields or coatings on the surfaces of the dry-type instrument transformers to eliminate any high voltage gradient on such surfaces. As will be apparent, such ground shields will reduce the danger of electrical shock and allow smaller metering enclosures.
It is therefore a primary object of this invention to provide potential taps for dry-type instrument transformers.
A further object of this invention is to provide potential taps for dry-type instrument transformers which are recessed in the insulation body of such instrument transformers.
A still further object of this invention is to provide potential taps recessed into the insulation body of dry-type instrument transformers and a connector module which will make dead-front electrical connection with such potential taps.
A still further object of this invention is to provide elbow-type connector modules having electrical conductors for mating with recessed potential taps of dry-type instrument transformers.
A still further object of this invention is to provide dry-type current and potential transformers, each having recessed potential taps and a pair of elbow connector modules for interconnecting the transformers for metering application.